1. Field of the Invention
The present invention relates to a hydraulic breather for a valve body of an automatic transmission, particularly to a hydraulic breather for use with a linear solenoid valve.
2. Description of the Prior Art
Generally, a valve body in an automatic transmission includes a lot of valves and is immersed in oil contained in an oil pan.
Operation of a solenoid such as a linear solenoid valve disposed in the valve body requires immersion in oil. The oil space within the solenoid cannot be sealed because of volume variations caused by the action of the solenoid.
Conventionally, a solenoid valve is directly immersed in an oil pan and is fixed to the outside of the valve body with bolts. Even in the case of a solenoid valve being disposed inside the valve body, the solenoid valve is immersed in oil received directly from the oil pan through a breathing hole.
However, as the oil in the oil pan contains foreign materials such as minute steel fragments from the lubricated gears, there may be cases when the foreign materials cause malfunction of the solenoid valve.
Particularly, a linear solenoid valve which requires precise and subtle operation is apt to be caused to malfunction by even a minute foreign material. Therefore it is strongly required that such a linear solenoid valve receive clean oil.